Every 305 I ever had was blue as well. I once looked at a 305 a guy had for sale claiming it was a 350 because he was told it was, well, the casting numbers told a different story, his not so intelligent employee, told me it was a 350, how did he know? "all 350`s from 62 to 72 were blue, didn`t you know that?" I replied with "no I didn`t, I also know they didn`t make a 350 until 1967, the same year the camaro was released"
As for all my engines now, I just do as the Rolling Stones said, Paint it black.